Currently, various electronic writing tools (digital pens) are put into practical use. For example, an electronic writing tool disclosed in Patent Document 1 (identified below) includes a tact switch that is disposed in a housing, and an operation button that protrudes to an outside of the housing. When an operator presses the operation button, a bottom surface of the operation button presses the tact switch. The tact switch is switched to an on state by this press. Thus, the device can detect that the operator is operating the electronic writing tool.
Patent Document 1: Japanese Patent Application Laid Open No. 2009-211552.
However, the electronic writing tool disclosed in Patent Document 1 uses an automatic switch, i.e., a mechanical switch, and therefore, a contact failure can occur due to a damage or temporal deterioration. Further, unless the operation button is reliably pressed by the operator with sufficient force and is brought in contact with the tact switch, the device will not reliably detect a holding state.